Multiple discharge-servo curve control method and device of electrical discharge machine

ABSTRACT

This invention mainly develops the multiple discharge-servo curve control method and device of electrical discharge machine. It comprises a storage unit, a setting unit, a reading unit, a program unit and instruction-judging unit. Herein the operator can dominate the program execution by using program calling method, and calls a discharge-servo curve instruction to satisfy with the real machining requirement. In order to achieve one-step processing with selectable multiple discharge-servo curve, this will swaps the discharge-servo curve from a system calling to a program calling.

BACKGROUND OF INVENTION

[0001] 1. Field of Invention

[0002] This invention mainly develops the multiple discharge-servo curvecontrol method and device of electrical discharge machine. Especially,it means a numerical control method used by the electrical dischargemachine, herein it will choose multiple discharge servo curves bycalling the discharge servo curve instruction during the machiningprocess. This application can be used for the electrical dischargemachine, the drilling electrical discharge machine and the wire-cutelectrical discharge machine.

[0003] 2. Description of The Prior Art

[0004] Electrical Discharge Machine (EDM) adopts the sparking generatedbetween the electrode and workpiece, and then melts as well asevaporates the material, under a locally instant high temperaturecondition, to achieve the cutting result, which is a non-traditionalmachining technology. Since EDM has already been adopted to treat a morecomplex and higher precision product by the industries worldwide, butthe precision control technique of EDM is still not good enough andneeds to be improved indeed.

[0005] The gap-voltage control-loop of the electrical discharge machinewill determine the suitable cutting speed by the real measurement of themoving and the calculating the deviation of the gap-voltage.

[0006] Moreover, FIG. 1 shows the functional block diagram of a knowngap-voltage control loop of the electrical discharge machine, wherein itwill calculate the gap-voltage difference between the real measurementand the operator inputs, and then outputs the cutting speed after theoutcomes are processed through the multiple discharge-servo curvecontroller and the deviation controller. Furthermore, the positioningcontrol-loop guides the electrical discharge machine to work on thecutting with a position command integrated by the integrator. Finally,it will issue a real gap dimension for calculating the gap deviation bysubtracting that real gap dimension with an original operator-input gapvalue, and calculates the gap-voltage by the gap and the gap-voltageconverter, and then subtracts that gap-voltage with the referredoperator-input gap-voltage. Recursively, the next gap-voltage controlcycle goes on, wherein the cutting speed corresponded to the gap-voltagedeviation, which is calculated by the internally used gap-voltagedeviation and cutting speed control curve of the multipledischarge-servo curve controller. The gap-voltage deviation and thecutting speed control curve are generally called as a discharge-servocurve. As shown in the FIG. 2, the discharge-servo curve is built on therelationship of the gap-voltage deviation and the cutting speed, andcontains a nonlinear discharge-servo curve 1 a and a lineardischarge-servo curve 1 b.

[0007] The multiple discharge-servo curve controller of electricaldischarge machine chooses a discharge-servo curve by the controlsoftware device of known electrical discharge machine software structureas shown in FIG. 3, and then that flowchart of known discharge-servocurve control method is shown in FIG. 4. Before initiate the program,the discharge-servo curve is set on the CNC control panel and thedischarge-servo curve data is recorded insider the multipledischarge-servo curve controller, and then cutting process goes onfollowing with the discharge-servo curve data which is recorded insiderthe multiple discharge-servo curve controller as soon as the programstarted.

[0008] The required cutting speed is different during the workpiececutting process, which dues to the different machining environment suchas a different material of electrode, workpiece, cutting solution,coarse or fine process. If the known discharge-servo curve controlmethod is adopted, the executing program has to be stopped in order toexchange a discharge-servo curve data, and then backs to set thedischarge-servo curve on the CNC control panel for swapping the recordinsider the multiple discharge-servo curve controller and thedischarge-servo curve data. Therefore, it is really not convenient tothe case of single workpiece with multiple discharge-servo curves.

[0009] Conclusively, how to allow an electrical discharge machinearbitrarily choosing the discharge-servo curve during the real cuttingprocess is sincerely a problem.

SUMMARY OF THE INVENTION

[0010] The main purpose of this invention can lead to solve theaforesaid defects. Adopt the program calling, this invented multipledischarge-servo curve control method and device of electrical dischargemachine will allow the operator to swap the different discharge servocurve in according with the real process requirement during theelectrical discharge machine working and to achieve the one-step processwith arbitrarily choosing the multiple discharge-servo curve.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a functional block diagram of a known gap-voltagecontrol loop of the electrical discharge machine.

[0012]FIG. 2 is a plot of the discharge-servo curve.

[0013]FIG. 3 is a configuration of known electrical discharge machinesoftware structure.

[0014]FIG. 4 is a flowchart of known discharge-servo curve controlmethod.

[0015]FIG. 5 is a flowchart of this invented multiple discharge-servocurve control method of electrical discharge machine.

[0016]FIG. 6 is a hierarchy of this invented control software structure.

[0017]FIG. 7 is a configuration of this invented multipledischarge-servo curve control device of electrical discharge machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] This invention is the multiple discharge-servo curve controlmethod and device of electrical discharge machine; the flowchart of thisinvented multiple discharge-servo curve control method shown in FIG. 5.Primarily set the discharge-servo curve database 11 whenever thebeginning 10 command is issued, wherein each gap-voltage deviation andits corresponded cutting speed of the discharge-servo curve are inputfrom the CNC control panel in order to set up the multipledischarge-servo curve database. The algorithm of the discharge-servocurve is constructed on the records of the gap-voltage deviation and thecutting speed that is under the real optimal processing condition.Moreover, correlated it with the collected gap-voltage deviation and itscutting speed that are under the different electrode material, differentworkpiece material, and different cutting solution. A polynomialequation is expressed with those gap-voltage deviations and itscorresponded cutting speeds as:

f(e)=a ₀ +a ₁ ×e+a ₂ ×e ² +a ₃ ×e ³ +a ₄ ×e ₄ +Λ+a _(n) ×e ^(n)

[0019] where f(e) is the cutting speed and e is gap-voltage deviation.The aforesaid polynomial equation is called as the discharge-servo curveequation, and it is used to set up the discharge-servo curve with lotsof different processing conditions. Moreover, defining thedischarge-servo curve parameter 12 is first set in the discharge-servocurve database to correspond a numerical value of the discharge-servocurve parameter; such as the 1^(st) discharge-servo curve corresponds toa numerical value of the discharge-servo curve parameter that is set as“1” in the discharge-servo curve database, and then set thatdischarge-servo curve parameter's value to be that discharge-servo curveaccording to the discharge-servo curve required under processenvironment. After all read the initial discharge-servo curve data 13,which is based on the discharge-servo curve parameter's value, then readits corresponded discharge-servo curve data from the discharge servocurve database and record it into the multiple discharge-servo curvecontroller. Input the processing program 14 after set and read thedischarge-servo curve data for the machining required, which is usingthe CNC control panel to key in the working instruction and thedischarge-servo curve instruction for processing program setup. Once theprocessing program finished the editing, it then starts the processingprogram 15. Beyond this moment, Program node for judging the workinginstruction 16 will be used to determine: when the program node is aworking instruction, it executes the working instruction 17, which isusing the discharge-servo curve data of the internal record of themultiple discharge-servo curve controller to execute the cuttingprocess, or when the program node isn't a working instruction, it willexecute the program node for judging the discharge-servo curveinstruction 18. Moreover, when program node is “discharge machiningNO.n”, access the discharge-servo curve data 19, which the n^(th)discharge-servo curve data will be accessed from the discharge-servocurve database and is then stored insider the multiple discharge-servocurve controller, wherein the “discharge machining NO.n” is called asthe discharge-servo curve instruction. Otherwise, it will finish theprocessing when program node isn't the discharge-servo curveinstruction. Conclusively, the discharge-servo curve instruction of theprocessing program presents how to call the discharge-servo curve whilethe processing program is running. Therefore, this invention allow theoperator to swap the different discharge-servo curve according with thereal process requirement during the processing and to achieve theone-step process with arbitrarily choosing the multiple discharge-servocurve.

[0020] During the processing, the software control device is designed tocontrol the discharge-servo curve, as shown in FIG. 6, wherein thisinvented software control device comprises a human-machine interfaceunit 21, a multiple discharge-servo curve control device 22, anoperation unit 23, an interpolation unit 24, a machine logic-controlunit 25 and a motion unit 26, which the multiple discharge-servo curvecontrol device 22 of the software control device controls thedischarge-servo curve.

[0021] In FIG. 7, this invented multiple discharge-servo curve controldevice of electrical discharge machine, which comprises a setting unit221, a storage unit 222, a program unit 223, an instruction-judging unit224 and a reading unit 225, wherein the storage unit 222 is used tostore the discharge-servo curve data, the setting unit 221 is used toset the parameter value of the discharge-servo curve. Referring to theparameter value of the discharge-servo curve that is kept in the settingunit 221, read the discharge-servo curve data from the storage unit 222by accessing through the reading unit 225. As far as the reading processis over, it will edit the working instruction and the discharge-servocurve instruction of the processing program, then to start theprocessing program. However, the execution of the processing programwill been executing with the discharge-servo curve data read from thereading unit 225. Whenever the processing program is started, theinstruction-judging unit 224 will judge the program node is either aworking instruction or a discharge-servo curve instruction. Using thedischarge-servo curve instruction, which edited by the program unit 223,wherein it is called to swap the different discharge servo curve dataaccording with the real process requirement during the processingprogram executing and to achieve the one-step process with arbitrarilychoosing the multiple discharge-servo curve.

[0022] All of the aforementioned are only parts of collected bettercases; it can't be defined to restrict this invention's claims.Furthermore, any modification and/or adjustment of this invention scopeare still belonged to this document.

What is claimed is:
 1. A multiple discharge-servo curve control methodof electrical discharge machine, which comprises of: (1) input all ofthe pairs of the gap-voltage deviation and its corresponded machineprecession rate of the discharge-servo curvature to build a multipledischarge-servo curve database; (2) define the numerical value of thedischarge-servo curve parameters, which is depended on the processingconditions and the required discharge-servo curve to define a numericalvalue for the discharge-servo curve; (3) according to the numericalvalue of the discharge-servo curve parameters, access the correspondingdischarge-servo curve data kept in the discharge-servo curve databaseand record it into the multiple discharge-servo curve controller; (4)input the processing instruction and the discharge-servo curveinstruction in order to setup the processing program; (5) program nodefor judging the processing instruction, and the processing instructionwill be executed by following the discharge-servo curve data that isstored insider the multiple discharge servo-curve-controller as soon asprogram node being a calling instruction; and then (6) program node forjudging the discharge-servo curvature, the n^(th) discharge-servo curvedata will be accessed from the discharge-servo curve database and isthen stored insider the multiple discharge servo-curve-controller asprogram node being a “discharge machining NO.n”.
 2. A multipledischarge-servo curve control method of electrical discharge machine,which comprises the content of claim 1, wherein the discharge-servocurve that is defined by the gap-voltage deviation and machineprecession rate of the real discharge machining records of the differentelectrode material.
 3. A multiple discharge-servo curve control methodof electrical discharge machine, which comprises the content of claim 1,wherein the discharge-servo curve that is defined by the gap-voltagedeviation and machine precession rate of the real discharge machiningrecords of the different work-piece material.
 4. A multipledischarge-servo curve control method of electrical discharge machine,which comprises the content of claim 1, wherein the discharge-servocurve that is defined by the gap-voltage deviation and machineprecession rate of the real discharge machining records of the differentcutting solution material.
 5. A multiple discharge-servo curve controlmethod of electrical discharge machine, which comprises the content ofclaim 1, wherein each discharge-servo curve owns its correspondednumerical value of the discharge-servo curve parameter set in thedischarge-servo curve database.
 6. A multiple discharge-servo curvecontrol method of electrical discharge machine, which comprises thecontent of claim 1, wherein the 1^(st) discharge-servo curve owns itscorresponded numerical value of the discharge-servo curve parameter setas “1” in the discharge-servo curve database.
 7. A multipledischarge-servo curve control device of electrical discharge machine,comprising: a storage unit, which keeps the discharge-servo curve data;a setting unit, which sets the numerical value of discharge-servo curveparameter; a reading unit, which access the discharge-servo curve datafrom the storage unit in according with the numerical value ofdischarge-servo curve parameter defined in the setting unit; a programunit, which provides the processing instruction of the machiningprogram, the editing of the discharge-servo curve instruction and theinitiation of the machining program, moreover it executes the work-piecemachining with the discharge-servo curve data; and aninstruction-judging unit, which judge the machining program node to bethe processing instruction or the discharge-servo curve instruction,obeying the discharge-servo curve instruction edited by the programunit, the processing program will call the discharge-servo curveinstruction to match the real machining needs, swap the discharge-servocurve information and upgrade to the one-step machining with selectablemultiple discharge-servo curves.